Manufacture of lightweight cylinders or containers



March 24, 193e.l A. R'QTHSCH'MITT 2,035,408

MANUFACTURE OF LIGHTWEIGHT CYLINDERS .OR CONTAINERS Original Filed July20, 1935 2 Sheets-Sheet 1 ATTORNEY March 24, 1936. A. ROTHSCHMTT2,035,408

MANUFACTURE OF LIGHTWEIGHT CYLINDERS OR CONTAINERS Original Filed July20, 1933 2 Sheets-Sheet 2 ICQ-L ff s INVENTOR ATTORNEY Patented Mar. 24,1936 PATENT OFFICE MANUFACTURE OF LIGHTWEIGHT OYLINDERS R, CONTAINERSAnton Rothschmtt, Irvington, N. J., assigner to Walter Kidde & Company,Inc., Bloomfield, N. J., a corporation of New York Original applicationJuly 20, 1933, Serial No.

Divided and this application March 9, 1934, Serial No. 714,761

5 Claims.

The present application is a division of applicants copendingapplication Serial No. 681,291, led July 20, 1933, for Manufacture oflight weight cylinders or containers, and embodies 5 that portion of theabove copending application which relates to the method aspect of theinvention, the invention as a whole having originally contemplated bothan improved method and apparatus for manufacturing an improved lightWeight cylinder or container for the transportation and storage offluids under high pressure.

It has long been realized that gas, such as carbonio acid gas,compressed under great pressure, has great potential advantages forairplane purposes, particularly for flotation if the plane descends uponwater, for motor starting, and for fire extinguishing.

The practical use of such gas in connection with airplanes has been madepossible by the provision of a light. Weight cylinder machined bothexternally and internally to al desired predetermined thickness andminimum Weight, it having previously been considered necessary that thecylinders have great Weight in order to Withstand the great internalvpressure and to comply with the previously existing regulations of theInterstate Commerce Commission.

However, in the method of producing light weight cylinders from a tube,which may either be open at both ends or closed at one end and open atthe other, comprising machining the tube internally and externally to aypredetermined thickness and pecking-in an open end of the tube toprovide a neck for the reception of a Valve or plug or the like,` thenecking-in operation has resulted in an undue thicknessof the cylinderin the `shoulder portion adjacent the neck, the

metal on the internal surface of the shoulder adjacent the neck of thecylinder being of poor quality and being in kany event superiiuous, .asv the strength of the kcylinder at this point is otherf wise sufficientwithout this additional metal. v

It is accordingly `an object of the present invention to provide ,alight weight cylinder HVfor the transportation and storage offiuidsvunder high pressure, said cylinder having a minimum of weight forany required strength.

It is a more speciiic object of the present invention to provide a lightWeight cylinder, of the type having at least one end necked-in torenceive a valve or yplug or the like, in which a min- .f

imum wall thickness in the shoulder of the cylinder adjacent a necked-inend Jis provided.V

It is a furtherobjectvof the invention` toprovide a` methodof'manufacturing a light weight (Cl. Bil-148.2)

cylinder with a minimum wall thickness in the shoulder portion adjacentthe necked-in end, comprising machining the external surface of theshoulder to a predetermined curvature and machining the internal surfaceof the shoulder 5 to a predetermined curvature, employing the externalsurface of the shoulder as the controlling gaging surface for theinternal surface machining tool.

Although the present application is directed m to the method aspect ofthe present invention, the invention as a whole contemplates theprovision of apparatus for enabling the method to be carried out.

It is therefore a further object of the inven- 15 tion to provide aninside surface machining tool for machining the inside surface of a highpressure gas container adjacent a neck end thereof after the containerhas been necked-in.

Another object is to provide an inside surface machining tool vformachining the inside surface of any hollow object, having an opening vdisposed axially of the inside surface to be machined, adjacent theaxially disposed opening.

Still another object is to provide an inside sur- 25 face machiningtoolfor machining any portion of the inside surface of any hollow objecthaving van opening disposed in an axial relationl to the inside surfaceto be machined. v r

y A further object of the invention is to provide 30 an inside surfacemachining tool for machining the inside surface vof a hollowobjecthaving an opening therethrough, comprising a supporting member adaptedto be inserted through the opening and a machining tool movably mountedon v3g; the supporting member andarranged to describe n an arc of anydesired curvature. l v v A still further object of thefinvention is toprovide any inside surface machining .tool fory machining the insidesurface of a hollow object 40r having anopening therethrough, comprisinga. supporting member adapted to be vinserted throughgthe opening and amachining tool piv- -otally carried by the supporting member 'and jadapted to be rotated on its pivot to any desired 45 v radial position.

- 'I'hese and other .objectsof the invention will become apparent as theinvention isdescribedin greater detail in connection with theaccompanying drawings wherein: y y A- Figure 1 is a longitudinalcross-sectional View through `ahigh pressure cylinder 'in accordance fwith the invention with an inside surfacey machiningtool, likewiseaccording to theinvention, for machining the inside surface of thecylinder 55 adJacent the neck end, shown in the position to start itsmachining operation.

Figure 2 is an external View corresponding to Figure l with a portionbroken away and in crosssection to show an intermediate position of themachining tool.

Referring rst of all to Figure l the reference numeral I represents acylinder or container for fluids under high pressure, which may be alight weight cylinder or container made by any suitable method, such ascupping a blank by successive drawing operations to form a cylinderclosed 'at one end, machining the cylinder internally and externally toa predetermined Wall thickness, and necking-in the open end of thecylinder to form a neck end 2 and a shoulder portion 3.

When a container is formed in this manner by necking-in the open end ofa tube, the better metal in the shoulder portion3 is formed on theexternal surface of theI shoulder, which is subiected to a. swaging,hammering, .or equivalent operation ior eilecting the requirednecking-in. The metal on the internal surface of the shoulder, beinginsufiiciently worked and being appreciably deformed during thenecking-in operation, is of poorer quality than the outer metal and is,in any event, superiluous, as the strength of the container at thispoint is otherwise sufdcient without this additional metal:

Therefore, in `accordance with the present inventio, the metal shown at4 on the interior surface of the shoulder 3 is machined away, forexample, back as far as the dash line 5, shown within the cross-sectionof the shoulder portion 3.

It will, of course, be at once apparent that special equipment isnecessary for accomplishing this internal machining operation, and thepresent invention not only includes a special tool for accomplishingthis machining operation, but likewise includes a method of preparing acontainer for receiving the machining tool and for obtaining an exactlypredetermined wall thickness o the shoulder 3 of the container.

The method of the present invention comprises boring the neck end 2 toan accurate predetermined diameter, as shown at 3, for receiving andguiding the inside surface machining tool, and machining, by means .ofany suitable tool not necessary to be shown here, the external surface 1of the shoulder portion 3 to a fixed predetermined curvature or contour,so that the external surface 'I may be employed as an indexing surfacefor controlling the machining operation of the inside surface machiningtool and for enabling the latter to machine the shoulder portion to anexactly predetermined wall thickness.

It is of course to be understood that, for effecting the desiredmachining of the internal surface of the shoulder oi' the container, thecontainer is mounted on a lathe having a suitable head-stock andsuitable means for guiding the container to cause it to run true. Thetail-stock and the tool for machining the inside surface of the shoulderare, however, peculiar to the present invention, and their constructionwill now be described.

'I'he reference numeral 3 represents a guide collar, shaped at 3 toconform to the curvature of the external surface 1 of the shoulderportion 3 oi' the container, and adapted to receive a spacer ring IIIand a coupling member II. The coupling member II is provided with a hubI2 which is bored at I3 to receive with a close running flt a bushingI4. The bushing I4 is provided with screw-threads I5 which cooperatewith corresponding screw-threads on a ring nut I3. which serves toprevent the bushing I4 from being accidentally withdrawn from thecoupling member II, there being normally a clearance at I1 between thering nut I3 and the coupling member Il The bushing I4 is also providedwith screwthreads I3 which engage cooperating screwthreads on amicrometer adjusting nut I3, which bears against a thrust ring 2II,between which and the coupling member II there is provided a ball thrustbearing 2|. Secured to the thrust ring 20 by means of screws 22 is ashield 23 for protecting the ball thrust bearing from dust and dirt.

The bushing I4 is bored at 24 to receive with a press fit the supportedend 25.of a boring bar 23, which is adapted to be passed with aclose-working iit through the bore 3 of the container. The boring bar 23may also be keyed to the bushing I4 as shown. The boring bar 23 isprovided with a ilange 21 adapted to seat within a bored out portion ofthe' bushing I4.

'I'he other end of the bore 24 of the bushing I4 is adapted to receivewith a slidingl fit the push -rod 23, to which is connected the push rodextension 23, which in turn passes through a bore 30 of the boring ybar23.

'I'he bushing I4 is provided with a keyway 33, the arrangementpreventing any rotary movement between the bushing I4 and sleeve 33,

but permitting longitudinal movement therebetween. The sleeve 33 isreceived within a bored out portion 34 of anadapter 35, seating'on ashoulder 33 within the adapter 35.

In order to prevent any rotary movement between the adapter 35 and thesleeve 33, there is provided a "fuse pin 31 adapted to be receivedwithin a slot 33 in the sleeve 33 and in a slot 33. in a shearing block43, which preferably is of hardened steel and is in the form of aninsert within a slotted portion 4I of the adapter 35. 'Ihe "fuse" pin 31is retained within the slots 33 and 33 by a ring-shaped cover plate 42,which paratively weak, so that if the machining tool,l

still to' be described, should jam during the ma,`

chining operation, the pin 31 will give way and permit rotary movementbetween the sleeve 33 and the adapter 35, thus preventing injury to themachining tool and its assembly. The reason for the need of the pin 31will be better understood when the method of operation ofthe machiningtool has been fully described.

'I'he adapter 35 is chambered at 44 and is bored at 45 to receive with arelatively loose flt the extension 43 on the push rod 23, there beingalso provided a washer 41 and a nut 43 secured to the extension 43. Acompression spring 43 encircles the push rod 23 and bears at one endwithin a bored out portion 53 of the bushing I4 and at the other end ona wall of the chamber 44 of the adapter as. The assembly at this pointis campleted by a ring nut 5I having a screw-threaded engagement withthe reduced end portion of the bushing I4 within the chamber 44 of themounted on the push rod 28, the screw 53 cooperating with the key slot52 for the purpose of preventngrotary movement of the push rod 28.

Referring once again to the boring bar 26 which is recessed at 54, thereis mounted within the recess 54 a tool holding member 55, the toolholding member being pivotally mounted on a pin 56 carried by the boringbar 26. The tool holding member is suitably chambered to receive a toolbit 51, which may be secured within the tool holding member 55 in anysuitable* manner, a backing screw 58 being provided to support the toolbit against inward movement during the machining operation. The backingscrew 58 may be reached for adjustment by the insertion of asuitabletool through the passage 59 in the end of the boring bar 26. Pivotallymounted on the pins 60 and 6I is the link 62, which serves to connectthe push rod extension 29 and the tool holding member 55.

In employing the tool as above described for machining the insidesurface of the shoulder of Aa high pressure gas container, the adapter35 is preferably secured upon the turret of the lathe, and the containeritself is suitably prepared and mounted in the manner already described,the surface 9 of the guide collar 8 being brought into engagement withthe external surface of the shoulder of the container, the boring bar26, of course, being inserted through the bore 6 of the container. Justbefore doing this, however, the tool bit 51 is carefully mounted withinthe tool holding member 55 so that the cutting edge of the tool is therequired predetermined distance from the center of the pivot 56 so thatit will describe the desired radius, not exceeding the internal radiusof the cylindrical portion of the container. After the tool and thecontainer have been assembled in the manner already described, themicrometer adjusting nut I9 is rotated in a direction to permit the toolto take a cut of the required amount olf the inside surface of theshoulder ofthe container. The turret of the lathe is then caused to beadvanced toward the container at thel required rate of speed, carryingwith it the push rod 28 and the push rod extension 29, by reason of theengagement of the adapter 35 with the shoulder 63.0n the push rod 29 andcausing the connecting link 62 to rotate the tool holding member 55 onits pivot 56, so that the cutting edge of the tool 51 moves radiallyoutwardly from the recess 54 in the boring bar 26, advancing over theinside surface of the shoulder of the container all during the time thatthe container is, revolved from the head-stock of the lathe. Assumingthat the material to be removed is more than can be taken in one cut, assoon'as one cutting operation has been completed, the cutting tool isreturned to its original position within the recess 54 under theinfluence of the compression spring 49, by backing olf the lathe turret,and the micrometer adjusting nut I9 is further adjusted to take anothercut, the adjusting nut I 9 being turned in the Adirection for moving thecutting tool closerto the inside surface to be machined.

By always machining the external surface of the shoulder 3 of thecontainers of a given size to a predetermined curvature or contour andby forming the surface 9 of the guide collar 8 to conform to theexternal surface of the shoulder 3, it is possible to determine how muchthe micrometer adjusting nut I9 must be rotated in order to cut therequired amount of material from the inside surface of the shoulder, andafter the required amount of turning of the micrometer adjusting nut I9has been determined, it is possible to machine the wall thickness of theshoulder to a predetermined thickness of great accuracy without constantchecking of the thickness of the shoulder; althoughV of course thethickness of the shoulder should be checked when the machining operationhas been completed.

A detailed description of Figure 2 of the drawings is not believed to benecessary, as this figure simply shows an external view corresponding toFigure l with a portion broken away and in crosssection to show anintermediate position of the tate, being secured as it is to the turretof the lathe. If, therefore, the machining cooly should become jammedwhile the container is revolving, it is desirable to guard the toolagainst damage,

and for this reason there is provided the comparatively Weak fuse pin31, which gives way in the manner previously described when any unduestrain is placed upon the machining tool.

It should also be noted that the invention is equally applicable tofluid containers closed on one end and necked-in on the other en d andto iiuid containers necked-in on both ends; and is, in fact, applicableto effecting machining of the inside surface of any hollow object havingan opening therethrough through which a machining tool may be insertedand manipulated; being further applicable to machining the side wall,the bottom wall or the shoulder of such containers or other hollowobjects.

It will of course be apparent that, while the invention has beendescribed with reference to one specific form of construction ofthemachining tool assembly, the latter may be carried out in otherequivalent forms of construction, so long as the machining tool may beinserted into the interior of the object to be machined, and so long asit can be moved to describe an arc of any desired curvature whethercircular or otherwise.

From the above description of both the method and one specificembodiment of the apparatusof 7 the present invention, it will beapparent that I have made broadly new and useful improvements in themanufacture of light weight cylinders or containers, and it willaccordingly be understood that I do not wish my invention to be limitedsave as defined in the appended claims.

I claim: A

l. The method of producing high pressure cylindrical metal containersfor uids under pressure from a tube open on at least one end whichcomprises machining the tube internally and externally to apredetermined thickness, closing-in an open end oftheV tube to provide ashoulder and a neck, and machining said shoulder to a predeterminedthickness to remove undesirable weight by machining the external surfaceof the shoulder to a predetermined contour and then machining theinternal surface of the shoulder to an also predetermined contour,employing the external surface of the shoulder as an indexing surfacefor adjustably controlling the machining of the internal surface and thethickness of the shoulder.

2. The method of producing high pressure cylindrical metal containersfor fluids under pres- 5 to a predetermined thickness to removeundedetermined thickness to remove undesirable 5 sirable weight bymachining the external surface weight by machining the external surfaceof the of the shoulder to a predetermined radius and shoulder to apredetermined contour and then then machining the internal surface ofthe shoulmachining the internal surface of the shoulder to der to analso predetermined radius, employing an also predetermined contour,employing the 1o the external surface of the shoulder as an inexternalsurface of the shoulder as an indexing 10 Adexing surface for adjustablycontrolling the masurface for adjustably controlling the machiningchining of the internal surface and the thickness of the internalsurface and the thickness of the of the shoulder. shoulder.

3. 'Ihe method of producing high pressure cy- 5. The method of producinghigh pressure 15 lindrical metal containers for fluids underprescylindrical metal containers for fluids under l5 sure from a tubeoperi on at least one end which pressure from a tube closed at-one endand open comprises closing-in an open end of the tube to at the otherwhich comprises closing-in the open provide a shoulder and a neck, andmachining end of the tube to provide a shoulder and a neck, saidshoulder to a predetermined thickness to and machining the shoulder to apredetermined 20 remove undesirable weight by machining the exthicknessto remove undesirable weight by ma- 20 ternal surface of the shoulder toa predetermined chining the external surface of the shoulder to acontour andvthen machining the internal surface predetermined contourand then machining the of the shoulder to an also predeterminedconinternal surface of the shoulder to an also predetou-r, employing theexternal surface of the shoultermined contour, employing the externalsurface 25 der as an indexing surface for adjustably controlof theshoulder as an indexing surface for ad- 25 sure from a tube open on atleast one end which comprises closing-in an open end of the tube toprovide a shoulder and a neck, for the reception of a valve or plug andmachining said shoulder ling the machining of the internal surface andthe thickness of the shoulder.

4. The method of producing high pressure metal containers for fluidsunder pressure from a tube open on at least one end which comprisesclosing-in, an open end of the tube to provide la shoulder and machiningsaid shoulder to a prejustably controlling the machining of the lnternalsurface and the thickness of the shoulder.

ANTON ROTHSCHMITI.

CERTIFICATE OF CORRECTION.

Patent No. 2,055,408. March 24, 1936.

' ANTON ROTHSCHMITT.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 4,first column, lines 3 and 4, claim 2, strike out the words "for thereception of' a valve or plug"; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to therecord of the case in the Patent Office. f I

Signed and sealed this 14th day of April, A. D, 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents.

5 to a predetermined thickness to remove undedetermined thickness toremove undesirable 5 sirable weight by machining the external surfaceweight by machining the external surface of the of the shoulder to apredetermined radius and shoulder to a predetermined contour and thenthen machining the internal surface of the shoulmachining the internalsurface of the shoulder to der to an also predetermined radius,employing an also predetermined contour, employing the 1o the externalsurface of the shoulder as an inexternal surface of the shoulder as anindexing 10 Adexing surface for adjustably controlling the masurface foradjustably controlling the machining chining of the internal surface andthe thickness of the internal surface and the thickness of the of theshoulder. shoulder.

3. 'Ihe method of producing high pressure cy- 5. The method of producinghigh pressure 15 lindrical metal containers for fluids underprescylindrical metal containers for fluids under l5 sure from a tubeoperi on at least one end which pressure from a tube closed at-one endand open comprises closing-in an open end of the tube to at the otherwhich comprises closing-in the open provide a shoulder and a neck, andmachining end of the tube to provide a shoulder and a neck, saidshoulder to a predetermined thickness to and machining the shoulder to apredetermined 20 remove undesirable weight by machining the exthicknessto remove undesirable weight by ma- 20 ternal surface of the shoulder toa predetermined chining the external surface of the shoulder to acontour andvthen machining the internal surface predetermined contourand then machining the of the shoulder to an also predeterminedconinternal surface of the shoulder to an also predetou-r, employing theexternal surface of the shoultermined contour, employing the externalsurface 25 der as an indexing surface for adjustably controlof theshoulder as an indexing surface for ad- 25 sure from a tube open on atleast one end which comprises closing-in an open end of the tube toprovide a shoulder and a neck, for the reception of a valve or plug andmachining said shoulder ling the machining of the internal surface andthe thickness of the shoulder.

4. The method of producing high pressure metal containers for fluidsunder pressure from a tube open on at least one end which comprisesclosing-in, an open end of the tube to provide la shoulder and machiningsaid shoulder to a prejustably controlling the machining of the lnternalsurface and the thickness of the shoulder.

ANTON ROTHSCHMITI.

CERTIFICATE OF CORRECTION.

Patent No. 2,055,408. March 24, 1936.

' ANTON ROTHSCHMITT.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 4,first column, lines 3 and 4, claim 2, strike out the words "for thereception of' a valve or plug"; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to therecord of the case in the Patent Office. f I

Signed and sealed this 14th day of April, A. D, 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents.

